The set-up of the ARC may have changed between series three and four, but James Lester was still there, sarcastically in charge. Ben Miller admitted to Paul Simpson during the filming of episode five that he was delighted to be back on Primeval, describing the show as “resurrected from beyond the dead!”

Once you knew Primeval was returning, did you talk to Adrian Hodges and Tim Haines about what was coming for Lester this year?

I did talk to Tim. What we all felt had been very successful in the third series was Lester having somebody to battle with, and we very much decided we’d like to have that element in this series.

The big change from Lester’s point of view is that rather than the ARC being a government-funded department, there’s this science and technology mogul, Philip, who has taken over the whole thing. It’s now a public/private partnership of the type that have proved universally disastrous across the whole of government!

Lester is now enmeshed in this messy situation where he has to deal with this mogul, who has a lot of say in what goes on in the ARC because he’s funding it. Lester is constantly compromised because this guy is his boss, so that’s been fun to play. He’s also dealing with the Minister, as ever, but this Richard Branson figure has his own agenda, and Lester constantly has to square things with him, and navigate around him. It’s fun for Lester too, because he loves politics.

The ARC also gets a massive upgrade and a major injection of funds, which doesn’t hurt in the sexiness of the whole thing. There’s this new building, a huge menagerie…

How much are you over in Ireland?

I tend to pop in and out. Everyone else is here all the time. I tend to do my scenes in blocks. I was here six weeks ago, and shot all my scenes for the first four episodes; now I’m doing episodes five and six this week.

You’ve got a new assistant this year in Jess, but you’ve had an assistant before , the infamous Oliver Leeke in series two…

And he was a great bad guy as well. It was such a great idea to have a weedy guy as the baddy. Karl Theobald was so fantastic, playing it so admirably straight. He kept the rigging taut all the way through it.

But Lester seems very lucky having these very glamorous women around – he had Jenny, now Jess. Jenny was more a PR girl, where Jess is running the day to day operations in the ARC, and the communications, which has now got ridiculously complicated. That bank of screens just gets bigger and bigger every series. She’s my right hand woman, who I get to be really sarcastic to a lot of the time.

Becker has become a more important character, much more developed than Captain Ryan was in the first series, and we’ve now got Ciaran as well, who brings a new element.

Douglas Henshall’s Nick Cutter was a thinking leader; Jason Flemyng’s Danny Quinn was more action first. Where does Matt fit between the two?

He’s a really interesting character – probably the most interesting character in this series. He’s quite mysterious. There’s elements of Helen Cutter in there: he is clearly not quite what he seems. He acts as if he’s just a beefcake man of action kind of person, but he’s got another agenda, and is actually keeping his cards very close to his chest. He’s very bright as well – and he’s very funny. He’s a witty, quipping character. And Ciaran is fantastic playing him. I can see aspects of lots of other characters: bits of Cutter, a bit of Helen in the hints at some other backstory. He’s very much pretending to be one thing with everyone. By episode five, we’re really getting into what he is up to.

Is Lester fooled by him?

I don’t think that Matt’s agenda is necessarily a bad one, it’s just “other”. Lester likes him, which is nice to play, because Lester hasn’t really liked most of the others. He quite liked Cutter, but didn’t want Cutter to know it; Danny he finds exasperating, but with Matt, he really likes and respects him. Cutter was pure emotion coupled to this raging intellect, a ferocious passion for the creatures and not caring so much for the people; Danny only cared about the people, and not the creatures. There’s something very attractive about Matt: he’s clearly smart and keeps himself to himself.

How is Lester with Abby and Connor now?

Very affectionate, more and more. He’s finding it harder and harder to convince them that he’s really the ogre that he once was. It’s a tremendous relief to him that they’re okay and they’re back. I think he even forgets how much Connor winds him up – I loved that bit in series three where Connor moved into the flat. Abby and Connor are an item now, which is an interesting development, because Andrew and Hannah are an item in real life. You can’t spend a year in the Cretaceous and not get it on!

Has the wit we saw in series three continued into this year?

Definitely. The show is growing up, in a way. There’s always been a strong comic element in Primeval; there’s some comedy in all good drama, and you don’t get good comedy without good drama in it. There’s a very funny scene we’re filming today [for episode five] where everyone is short-handed, and Lester decides he’s going to try to help run the navigation screen. There’s some really good stuff in it where he’s trying to give orders. Lester is a great character to have fun with like that because he takes himself so seriously.

The other thing that has gradually changed over the course of the series is Lester’s affection for the team, which we’ve glimpsed at various times. He would hate anyone to know it, and he affects a kind of callousness, but what’s become more and more apparent is that that’s a cover for actually really caring about the whole thing, but knowing how best to deal with people politically.

There used to be two types of teachers at school: the ones who’d try to be your friends, who you’d never like; and the ones who would be very stern and strict when you had them in the first form, but by the fourth form, they were starting to show their human side, and you adored them by the fifth form. And they’re the ones you kept in touch with. I think Lester is one of those teachers.